Well casing perforator



June 4, 1940. M. F. ALol WELL CASING PERFORATOR Filed June 26, 1939Patented June 4, 1940 UNITE STATES 13 Claims.

My invention relates to a Well casing perforator of the gun type and hasfor its principal object, the provision of a relatively simple andpractical casing perforating device including a body that is adapted tobe lowered into well casing to the desired depth and, said body carryinga plurality of projectiles and an explosive charge which when ignited byan electric spark res said projectiles outwardly through the wall of thecasing, thereby perforating the same and, said projectile carrying bodycarrying means for producing the electric spark required to re theexplosive charge, thus eliminating al1 electrical connections betweenthe gun-like member that is lowered into the casing and the groundsurface at the top of the Well hole.

A further object of my invention is, to provide simple and convenientmeans, preferably a weight that is permitted to slide by gravitydownward on the cable that is utilized for lowering the perforator intothe casing and which weight is effective in imparting motion to theelectric spark producing means carried within the perforator so as toeffect the firing of the explosive charge.

A further object of my invention is, to provide simple and eflicientmeans for rendering the explosive charge firing means ineffective so asto prevent accidental or premature ring of the charge while theperforator is being assembled and made` ready to be lowered into thecasing.

With the foregoing and other objects in view, my invention consists incertain novel features of construction and arrangement of parts thatwill be hereinafter more fully described and claimed and illustrated -inthe accompanying drawing in which:

Fig. l is a vertical section taken through the center of a casingperforator constructed in accordance with my invention.

Fig. 2 is an elevational view of the upper end portionof the perforatorand looking in the direction indicated by the arrow 2 in Fig. 1.

Fig. 3 is a plan view of the perforator.

Fig. 4 is a vertical section taken through the center of the Weight thatis utilized for electing operation of the electric spark producingmeans.

Fig. 5 is a horizontal section taken on the line 5-5 of Fig. 4.

Fig. 6 is an enlarged horizontal section taken on the line 6-6 of Fig.1.

Fig. 7 is an enlarged vertical section taken on the line 1-1 of Fig. 3.

Fig. 8 is an enlarged vertical section of the lower end portion of theperforating device.

Referring by numerals to the accompanying drawing which illustrates apreferred embodiment of my invention, IIl designates a body, preferablycylindrical in form and composed of metal and which may be of anydesired and convenient length. 'Ihe diameter of this body is such thatit will readily pass downward through oil well casing of standard sizes.

Formed in the upper portion of body I is a chamber II and, leading fromthe lower end of said chamber to the lower end of body II) is an axialbore I2.

A head I3 is removably seated, preferably by being screw seated in theupper portion of chamber I I, and removably seated in the center of thishead is a socket I4 to which is suitably connected, the lower end of acable I that is utilized in lowering the perforator into the casing.

Arranged to slide freely through a vertically disposed bore I6 that isformed through head I3 to the side of socket I4, is a plunger I'l, theupper end of which is enlarged to form a head I8 through the centralportion of which is formed an aperture I9. An expansive spring 20surrounds the upper portion of plunger I1 and bears against the lowerend of the head I8 and against a shoulder 2I that is formed in the upperportion of the bore I6, thus normally maintaining the plunger inelevated position. i

Plunger I'I passes through a fluid pressure tight gland or stufng-box 22that is arranged in the lower portion of head I3 and, that portion ofthe plunger that projects below said gland is provided with rack teeth23. These teeth engage the teeth of a pinion 24, which latter is xed onthe armature shaft of a conventional magneto 25.

While plunger I1 is in its normal position or at the upper end of itslimit of movement, the teeth of pinion 24 engage the lowermost teeth ofrack 23. An opening formed in the wall of body IU surrounding chamber II directly opposite the central portion of the magneto and which openingis closed by a readily removable plug 26, gives access to the magnetofor the purpose of inspection, adjustment, repairs, etc.

Removably positioned in the aperture I9 in head I8 is a' pin or key 2'Ithat serves to secure the plunger in its elevated position and preventthe same from being accidentally moved downward to operate the magnetowhile the perforator is being charged and made ready for use and beforeit is inserted in the upper end of the well casing.

Formed through that portion of the perforator body I0 through which thebore I2 passes are radially disposed apertures 2B, preferably disposedin spaced and staggered relation and which serve prising a thin walledcasing 32 containing a` charge 33 of explosive substance, such as gunpowder. Embedded in the explosive charge 33 isa plate 34 of insulatingmaterial, carrying .a pair of spaced spark terminals 35. The upper oneof these terminals is connected by a conductor 36 to a contact 31 thatis seated in the top of casing 32 and, when the casing is properlypositioned in bore i2 this contact 31 directly engages a contact 38. Y

This contact 38 is carried by the lower end Vof a pin or rod 39 formedof metal: and serving as a conductor for electric current and, whichpasses through that portion of the body i0 between the upper end of boreI2 and the lower 'portion of chamber II. This conductor 39 is suitablyinsulated from the metal in body I0, preferably by a sleeve 40 ofinsulating material.

One side of the magneto is grounded on the body I0 while the other sideis connected by a conductor 4i to the upper end of conductor 39.

The lower end of the cartridge receiving bore or chamber 23 is closed bya screw plug 42, there being a packing ring or gasket 43 arrangedbetween the upper portion of said plug and the body i0 around the lowerend of bore I2 and, arranged for sliding movement in the upper portionof this plug is an axially arranged pin 44 prbvided on its upper endwith a head 45. An expansive coil spring 46 is arranged between the heade5 of contact pin 44 and a shoulder 41 that is formed in the upperportion of plug 42 around the aperture that receives said contact pin.

Seated in the lower end of the cartridge that is positioned in bore I2is a contact pin '48 provided on its lower end with a head 49 and, whichlatter engages the head 45 of the spring-held contact pin 44.

Connecting contact pin 48 with the lower one of the spark terminals 35is a conductor 50.

The means utilized for forcing plunger I1 downward to operate themagneto is illustrated in Fig. 4 and 5 and comprises a two-part weight5I substantially cylindrical in form and, the two parts of which arehingdly connected to each other, preferably by a vertically disposedhinge pin 52. The two parts of the weight are normally held in closedposition by means of a hook 53 that is hinged to one of the parts of theweight and which engages in a recess 54 in the other part (seeA Fig. 5).Formed in the lower portion of this weight is a chamber 55 open at itslower end and which is of such size as to receive the socket I4 and,formed through the upper portion of said weight is an axial opening 56that receives the cable I5 that carries the perforator.

To load the perforator, key 21 is inserted through opening I9 in head I8so as to prevent the plunger from being moved downward to operate themagneto and the projectiles 29 are now inserted in their chambers 28,after which the disc-like closures 3l are pressed into the recesses 32.thereby closing the projectile containing chambers.

The explosive cartridge vis now inserted in bore I2 and plug 42 is screwseated in the lower end of body III and, when so seated the spring-heldcontact 45 engages contact 49 on the lower end oi' the cartridge and thelatter is maintained in the bore I2 with contact pin 31 in engagementwith contact 38.

Just before the perforator is lowered into the casing, the key 21 isremoved from head Il, thus leaving plunger I1 tree to move downward asa.

result of the engagement of the weight 5I with said head at thetermination of its travel down the cable I5.

The perforator is now lowered into the well casing by propermanipulation of cable I5 and, when said perforator has reached the depthat which the casing is to be perforated, the two-part weight 5I isopened and afterbeing applied to A the cable the parts of the weight areclosed and held in such position by the engagement of t free end of hook53 in recess '54.

The weight is now released and by gravity it will slide down the cablefrom which the perforator is suspended and, when the weight reaches 4theupper end oi' the perforator it will strike the top of head I8, therebymoving the same and plunger I1 downward and, the engagement of the rack23 with pinion 24 will actuate the armature of the magneto so as toproduce an electric spark between the terminals 35. As thel spark isproduced between the sparking terminals, the explosive charge of thecartridge will be iired and the resulting force will drive theprojectiles 29 outwardly from their chambers through the adjacent wallof the casing so as to perforate the same, thereby accomplishing thevdesired results.

After the casing operation as just described has been accomplished, theperforator is withdrawn from the well by means of cable I5 and saidperforator may be re=used after the chambers 25 have-been relled withprojectiles and a cartridge inserted in bore or chamber I2.

A particularly advantageous feature of my ime proved perforator is themounting of a magneto or other spark producing means within or directlyupon the perforator, for by such provision the requirement for sparkproducing means including electrical conductors extending from the topof the well hole downwardly therethrough to the perforator and whichdistance may be several thousand feet, is entirely eliminated.

Thus it will be seen that I have provided a casing perforator that isrelatively simple in construction, inexpensive of manufacture and veryeective in performing the functions for which it is intended.

It will be understood that minor changes in the size, form andconstruction of the various parts of my improved well casing perforator,may be made and substituted for those herein shown and described,without departing from the spirit of my invention, the scope of which isset forth in the appended claims.

I claim as my invention:

1. A casing perforator comprising a body provided with a chamber for thereception of an explosive charge, there being chambers formed in thebody for directing the force of the exploded charge laterally againstthe well casing in which the perforator is positioned, projectileslocated in said last mentioned chambers and magnets aclll tuated meanslocated wholly within said body and operable from the exterior thereoffor producing an electric spark within the explosive charge.

2. In a casing perforator the combination with a body, of a cableconnected to said body for lowering the same into well casing, anexplosive charge contained within said body, there being chambers formedin the body for directing the force of the exploded charge laterallytoward the well casing, projectiles located in said chambers, magnetoactuated means carried by the body for producing an electric spark inthe explosive charge and means adapted to slide down the cable to saidbody for actuating the spark producing means.

3. A casing perforator as set forth in claim 1, with means for renderingthe spark producing means inoperative while the body is being loaded foruse and before it is lowered into the well casing.

4. In a casing perforator, a body adapted to be lowered into wellcasing, an explosive charge contained within said body, there beingchambers contained in said body for directing the explosive force ofsaid charge laterally toward the surrounding well casing and meansincluding a magneto carried by said body for producing an electric sparkin said explosive charge.

5. In a well casing perforator the combination with a body, of a cableconnected to said body for lowering the same into well casing said bodycontaining an explosive charge, there being chambers formed in said bodyfor directing the force of the exploded charge toward the well casingsurrounding said body, projectiles in said chambers, means including amagneto carried by said body for producing an electric spark in saidexplosive charge and a member adapted to travel downward on the cablethat carries said body for actuating said magneto.

6. A well casing perforator as set forth in claim and with means forrendering the spark producing means inoperative while the body is beingmade ready for use and before being lowered into the casing.

7. In a well casing perforator, a body, an explosive charge containedwithin said body, there being chambers formed in said body for directingthe explosive force of said charge outwardly toward the well casing inwhich the body is suspended, projectiles located in said chambers, apair of spaced ignition points located in said explosive charge andmeans carried by the body for generating an electric current and causingthe same to pass through said ignition points and the spark gap betweenthe same.

8. A casing perforator as set forth in claim 7, with a cable connectedto said body for lowering the same into well casing and means adapted totravel downwardly upon said cable for actuating said sparkv producingmeans.

9. In a well casing perforator, a body, an explosive charge containedWithin said body, there being chambers formed in said body for directingthe explosive force of said charge outwardly to- Ward the well casing inwhich the body is suspended, projectiles located in said chambers, apair of spaced ignition points located in said ex plosive charge andmeans including a magneto carried by the body for generating an electriccurrent and causing the same to pass through said ignition points andthe spark gap between the same.

10. A well casing perforator as set forth in claim 9, with a cableconnected to said body for lowering the same into well casing and meansadapted to travel downwardly upon said cable and to actuate the magnetoof said spark producing means.

11. In a well casing perforator, a gun body including a plurality of gununits arranged to discharge laterally from said body, said gun unitsincluding an explosive charge receiving chamber and a plurality ofprojectile receiving chambers that communicate with the explosive chargereceiving chamber, an electric circuit including a pair of spaced sparkterminals located within the charge occupying said explosive chargereceiving chamber and magneto means carried by said gun body forenergizing said circuit and producing an electric spark between saidspaced spark terminais.

12. A well casing perforator as set forth in claim 1,1 and with meansfor actuating said magneto means from the exterior of said perforator.

13. In a well casing perforator, a body provided with a chamber for thereception of an explosive charge, said body being provided with aplurality of projectile receiving chambers that communicate with theexplosive charge chamber and magneto means carried by said body forproducing an electric spark within the charge located within saidexplosive charge receiving chamber.

MILLIO F. ALOI.

